As the world's population increases, the need to supply goods and services becomes increasingly complex. In order to adequately distribute products, it is necessary that they be sufficiently packaged to protect the integrity of the product, to provide a uniform quantity, to facilitate transport storage and display and to increase convenience to the purchaser/user.
Various industries employ a wide variety of packaging techniques for their various goods. Examples of such packaging techniques include boxes and cartons, paper and plastic bags, jars and bottles, metal cans, tubes, shrink wrapping and blister packs to name a few. A particular problem arises where a manufacturer seeks to package viscous materials. For example, where a viscous material is metered into a container, air can become entrapped in cavities resulting in either a short fill of the package or an overflow condition which fouls the dispensing equipment. This is of particular concern with viscous materials since, due to their relatively high surface tension, the materials tend to cling together and to the dispensing equipment with which they become in contact.
Examples of viscous materials for which accurate dispensing has value may be found in the food industry and include such viscous products as butter, peanut butter, jellies, cheeses, etc. In the cosmetic and personal hygiene industry, these viscous materials may include thick lotions, gels, creams, toothpastes, shampoos and the like. Household chemicals include such diverse products such as shoe polish, greases, soaps, hand cleaners and the like. In the industrial chemical industry, examples of viscous materials may include greases and other petroleum products, sealants, adhesives and a host of other products. All of these industries experience difficulties with automated packaging equipment, and the present invention is directed to providing improved dispensing equipment for these industries, although this invention is not limited to these industries, alone.
Many containers used by manufacturers to package their product are cylindrical in shape having hollow interiors within which to receive dispensed product for package. The present invention is particularly adaptable to these types of packages, whether they be cans, bottles or, as is often the case, a squeeze tube container also known as the "toothpaste-tube" container. In such squeeze tubes, an elongated tubular body is closed at one end, for example, by a nozzle or spout that defines a downstream end for the tube, when finished, out of which product is dispensed by a user. Product is filled in such tube from the spout end upwardly to an open end by a dispensing nozzle. The open end is then sealed by a crimping or heat sealed process flattening the upstream end of the squeeze along a diameter thereof. Due to the length of these squeeze tubes, relative to their width, the accurate dispensing product, especially viscous product, is particularly difficult.
When dispensing product into containers, especially elongated squeeze tubes, it is known in the industry to be desirable to start the dispensing at the bottom of the container when it is placed on a support and to withdraw the dispensing nozzle as product is discharged into the container so that the manufacturer gets a "bottom to top" fill. This helps eliminate cavitation and the attended problems noted above. However, it has been found difficult to accurately match the rate that available volume is displaced in the container, as measured by the cross-section of the container times the linear rate of withdrawal of the dispensing nozzle, with the volume discharge rate of the product from the dispensing nozzle. Various cam and linkage systems are known to attempt this procedure. Equipment employing the cam and linkage systems are typically difficult to adjust for accurate volume flow rates. Moreover, it is difficult and time consuming to reset such filling apparatus for containers of different diameters and lengths.